It is known for technical devices to be designed in a redundant form when high availability is required. This also applies to rail vehicles which are designed to be redundant to the extent that they have a second control computer in addition to a first control computer. Various appliances in the rail vehicle can be controlled via the rail vehicle's own data line network by the control computers; these appliances may be functionally important appliances or appliances which are not necessarily required for functionality of the rail vehicle.
In order to avoid more than one computer carrying out the function of a master in a control network such as this, it is known for the control computers to be coupled to one another via more than one physical connection (redundant connection). This redundant connection can be used to identify whether the second control computer, which is acting as a standby computer, has failed, or whether there is a communication fault.